International journal of Agronomy and Plant Production. Vol., 4 (5), 1023-1028, 2013Available online at http:// www.ijappjournal.comISSN 2051-1914 ©2013 VictorQuest Publications

Long term effects of municipal wastewater irrigation on some propertiesof a semiarid region soil of Iran.

Hamid Mollahoseini

Soil and Water Department, Isfahan Agricultural and Natural Resourses Research Center, Isfahan P.O.Box81785-199, Iran

*Corresponding Author: Hamid Mollahoseini

Abstract

In order to investigate the effect of long term irrigation of wheat farms on the soilproperties a field study was carried out in Varamin Station located in south of Tehran,Iran. The soil samples collected from the area with 29 years using wastewater irrigationand comparing the results with soil properties extracted from. previous control profilepedology study in 1981. Some Soil properties of samples. such as electricalconductivity(EC), soil reaction (pH), organic carbon (OC), bulk density (pb), saturatehydraulic conductivity(Ks) were measuresd for comparison. The obtained paired dataanalyzed with T-test. The results showed that using of wastewater increased the soilorganic carbon and bulk density in depth of 0-20 centimeter significantly (p<0.05).Saturated hydraulic conductivity in depth of 0-20 centimeter and soil reaction in bothdepth of 0-20 and 20-40 centimeter decreased significantly (p<0.05). The reason may bedue to filling of colloidal particles suspended in wastewater within the soil porosity.Wastewater quality and possibly, soil properties appear to play an important role in theeffect of using wastewater irrigation on the soil physical properties.

Keywords: irrigation, municipal wastewater, physical properties

Introduction

Arid and semiarid regions are characterized by exceeding of the evapotranspiration rate rather thanprecipitation during most of the years. Therefore, agriculture in these regions depends on supplementaryirrigation to enable crop growth production. At the same time, one of the main environmental problems inthese regions is a shortage of freshwater, which is expected to become more severe in the next futurebecause of the growing demand of different segments for water. Decly of water resources, as well asdrought and climate change make the problem more severe and critical. In these regions, one of thechallenges facing agricultural practice, which need large amounts of water, is finding new water resourcesfor irrigation. In recent years one of the alternatives of supplying water resources could be reuse of treateddomestic swage (effluent) for irrigation (Lado& Ben-Hur,2009). Irrigation with municipal wastewater couldchange soil properties that play an important role on the amount and availability of nutrients present in theapplied wastewater (Magesan et al. 1998). In particular, soil physical properties such as texture, structure,porosity and hydraulic conductivity will influence soil water content and aeration which in effect control thetype and rate of soil microbial activity and chemical reactions (Magesan, 2001). A growing demand of waterfor irrigation of agricultural lands has increased the reuse of treated and/or untreated municipal wastewater.Wastewater has been widely used for agricultural irrigation in china and in countries located in arid and semi-arid area as reported by Chen et al (2004). The wastewater irrigation provides water, nitrogen; phosphorusas well as organic matter to the soil (Siebe, 1998) All these factors will have beneficial effects on soilmicrobiology. Wastewater from municipal origin is rich in organic matter and also contains appreciableamounts of macro and micronutrients (Tabari&Salehi, 2009). However, there are some challeges about salt,heavy metal and surfactants which can accumulate in the soil (Siebe & Cifuentes,1995). The effects ofindustrial and municipal wastewater on agricultural soils have been documented, mostly with regard to heavymetal concentration (Domlngues & et al, 2004; Yang,2002). The reduction in soil hydraulic conductivity notonly affects downward movement through a soil profile, but can also affects water movement across the soil

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profile (Coppola & et al, 2004). Many studies have investigated various soil physical and chemical propertiesin the area of irrigated with wastewater. Several authors have studied the effects of effluent irrigation on thesoil chemical and physical properties (Dawes and Goonetilleke, 2006; Heidarpour et al., 2007), including soilhydraulic properties (Vinten et al., 1983; Cook et al., 1994; Tarchitzky et al., 1999; Magesan et al., 1998,2001; 2002; Lado et al., 2005; Gloaguen et al., 2006; Gharaibeh et al., 2007; Bhardwaj et al, 2008; Mandalet al., 2008). Among the potential risks associated with irrigation with treated wastewater are degradation ofaggregate stability, resulting decrease in soil hydraulic conductivity and compaction decrease in soil aerationincrease in runoff and finally increasing soil erosion (Tarchitzky & Golobati,1999). Despite the diversity in theorigin of wastewater, it has been established that 40 to 50 % of the dissolved organic matter (DOM) inIsrael's high load organic matter (OM) wastewater were humic matters. (~25% fluvic acids, ~ 11% humicacids, and ~7.5% hymathomenanice acids)(Rebhum,&Manka,1971). Suspended solids present inwastewater may filled pore spaces and physically blocked water conducting pores, thereby leading to asharp decrease in soil hydraulic conductivity (K)(Vinters,1983). Filling of the pores occurs mostly in the uppersoil layer (Siegrist,1987). opposite finding have been reported concerning the effects of dissolved organicmatter on the soil structural stability. It was suggested that organic substances have been considered ascementing agents that improve aggregate stability (Goldberg & et al, 1988). Humic substance, however,have been observed to have a dual effects as aggregating and disaggregating agents (Oades, 1984). Somestudies have indicated that duality effects may be related to the concentration of humic substances; at lowconcentrations (<0.05-0.10 g kg-1) the humic substances stabilize the aggregates, while at higherconcentrations they have a dispersive effect (Piccolo & et al,1996). Another soil property that can be affectedby effluent irrigation, and that could influence soil structural behavior and hydraulic properties is soil organicmatter content: An increase in organic matter content in the soil increased the aggregate stability (Lado etal., 2004b), and prevented the decrease of saturated hydraulic conductivity (Ks) during leaching of the soilwith deionized water (Lado et al., 2004a), and seal formation under rainfall (Lado et al., 2004b). Jueschke etal. (2008) studied the effect of irrigation with secondary effluents on soil organic matter content in fourlocations in the semiarid region of Israel. The effect of effluent irrigation on the organic matter content in thetopsoil (0–20-cm layer) was inconsistent among the various studied sites. Similar results were obtained byGharaibeh et al. (2007), who found inconsistent effects of effluent irrigation on organic matter content in aclay topsoil (0–0.3 m) near Ar-Ramtha (Jordan).In the present study, the long term influence of using municipal wastewater as irrigation water on soilproperties was studied and the soil properties in 2010 were compared with the same results of Control profilein pedology studies (1981), using T-test.

Materials and Methods

Site descriptionThe soil samples (Typic Haplogypsids, Soil Survey Staff 2003) were collected from the surface horizon

(0-20cm) and subsurface horizon(20-40cm) of a 100 ha of wheat farms under 29 years municipal wastewaterirrigation located 5 km south of Tehran, Iran(35o37' N, 51o 23' E) with elevation of, 1005 m above sea level.The climate of studied site is semiarid with mild cold winters and a seven month dry season (mid-April tomid-November). Average annual rainfall and average annual temperature are 232 mm and 13.3oC,respectively. The highest rainfall appeared in March and the lowest in August. The warmest month occuredin August and the coldest in January.

Soil samples analysisSoil samples were air dried and sieved using a 2mm-mesh stainless steel sieve. Physical and chemical

properties of the soil were determined methods using in pedology studies (1981). Soil ECe and pH wasmeasured in saturation extract with swiss made metrohm instruments. Organic carbon was determined bywet oxidation Walkley and Black's rapid titration method. Saturated hydraulic conductivity was measured bystandard method (Gupta and Dakshinamurthi,1989). Bulk density was measured by cloud and paraffin.

Statistical analysisThe paired data of measured soil parameters including soil electrical conductivity (ECe), soil reaction

(pH), organic carbon (OC), bulk density (pb), saturated hydraulic conductivity (Ks) in year 2010 and dataextracted from control profile in pedology studies (1981), were compared with T-test.

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Results and discussion

Soil reaction, organic carbon, saturated hydraulic conductivity and bulk density have shown in fig. 1 to 3respectively. soil properties base on paired data in 1981 and 2010 in 0-20 and 20-40 centimeter depth andtheir comparison based on t student values were shown in table 1.

Table1: Comparison of soil properties base on T-Test in 1981 and 2010

Soil reaction (pH)Soil reactions decreased from year 1981 to 2010 in all depth (0-20 and 20-40 cm). Significantly (p<0.05).

Soil reaction in topsoil (0-20cm) and subsoil ((20-40cm) were 7.9 and 8.2 in year 1981, where these valueswere 7.8 and 7.9 in year 2010 respectively (fig,1).The reason for decreasing of soil pH may be due to decomposition of organic matter and production oforganic acids in soils irrigated with wastewater (Vaseghi et al., 2005). This suggestion was supported by thefinding of Vaseghi et al. (2005) and Khai et al. (2008). In the soil treated with wastewater, addition of organicmatter in topsoil is more than subsoil . Waste water from municipal origin is rich in organic matter and alsocontains appreciable amounts of macro and micronutrients (Gupta et al,1998). Other researchers found thatsoil pH decreased with wastewater irrigation due to the oxidation of organic compounds and nitrification ofammonium (Mohammad&mazahreh,2003).

Electrical Conductivity (EC)Electrical conductivity of topsoil did not show any difference from 1981 to 2010 significantly (p<0.05)

where these values for subsoil changed from 1 ds m-1 to 1.6 ds m-1 respectively (p<0.05) (fig. 1).Accumulation of soluble salt, heavy metal and surfactants in the soil as a result of using wastewater wasreported by Siebe, and Cifuentes,1995.Tabari and Salehi (2008) reported the electrical conductivity (EC) of municipal waste water ranged from 1.78to 2.12 dS m-1 with the greatest value detected in August. Mohammad and Mazahreh(2003) stated that theincrease in EC for soil irrigated with wastewater compared with soil irrigated with fresh water attributed to theoriginal high level of total dissolved solid (TDS) of the wastewater. The highest value was observed with 10years of wastewater irrigation with tendency to be the higher with longer period of wastewater irrigation. Inaddition, soluble salts were accumulated more in the deeper soil layers due leaching the soluble salts intodeeper depth (Abu-Awwad,1996).

(a) (b)Fig1: Status of soil reaction (a) electrical conductivity (b) of topsoil and subsoil in years 1981 and 2010

2010198120101981t-valueDepth(Cm)Depth(Cm)Depth(Cm)Depth(Cm)df

Properties

20-4020-40

t-value

0-200-206.9**7.98.22.7*7.87.918PH2.5*1.61.00.5ns1.71.618EC(ds m-1)9.2**0.70.36.5**1.10.618Organic Carbon(%)0.9ns31.526.36.1**13.529.418saturated hydraulic(mm h-1)0.0ns1.31.32.9*1.41.318Bulk density(mg cm-3)

7.9

8.2

7.8

7.9

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

0-20 20-40Depth(cm)

Re

ac

tio

n(p

H)

1981 2010

1.6

1.0

1.7 1.6

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0-20 20-40Depth(cm)

Sa

lin

ity

(ds

.m^

-1)

1981 2010

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Organic carbon (OC)The results of fig 2 showed that the soil organic carbon increased in all depth (0-20 and 20-40 cm). from

year 1981 to 2010 significantly (p<0.05). In the year 1981 soil organic carbon in topsoil (0-20cm) and subsoil(20-40cm) were 0.6 and 0.3, where in year 2010 these values were 1.1 and 0.7 percent respectively. Thewastewater irrigation provides water, nutrient, nitrogen, phosphorus as well as organic matter to the soil(Siebe,1998).Soil organic carbon (SOC) is the most important indicator of soil quality playing a major role in nutrientcycling (rattan,2005). Addition of organic matter to the soil caused improving the physical, chemical andbiological characteristic of the soil so that, a better nutrient absorption will accelerate the crop growth (Wangand Wang, 2005). Tabari and salehi(2009) showed that SOC and CaCO3 were greater in needles of treesirrigated with municipal waste water compared with those irrigated with well water. Mohammadrusan and etal(2007) reported that soil organic matter content (OM) significantly. (p<0.05) increased with wastewaterirrigation application and depending on the period of application. Organic content in the soil also increasedas the number of irrigations increased, showing a benefit to the soil (wang& et al,2007).

Saturated hydraulic conductivity(Ks)Topsoil saturated hydraulic conductivity in year 1981 was 29.4 mmh-1 where this value in year 2010 was

13.5 mmh-1 (fig 2b). Cook et al(1994) reported the decrease of hydraulic conductivity in soil, due towastewater irrigation. Lado(2009) showed the direct and indirect effects of wastewater irrigation on soilhydraulic properties are closely related to both wastewater and soil properties. The reduction in soil hydraulicconductivity not only affects water infiltration through the soil profile, but can also affects water movementacross the landscape (Coppola&et al,2004). Suspended solids present in wastewater may accumulate andphysically block water conducting pores, thereby leading to a sharp decrease in soil hydraulic conductivity(Vinters,1983). Blocking of the pores occurs mostly in the upper soil layer (Siegrist,1987).

29.426.3

13.5

31.5

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Saturatedhydraulicconductivity

(mm.h-1)

Depth(cm)0-20 20-40

1981 2010

(a) (b)Fig 2: soil organic carbon (a) and hydraulic conductivity (b) of topsoil and subsoil in year 1981and 2010.

Bulk density (BD)Soil bulk density of topsoil (0-20cm) increased from 1.3 g cm-3 to 1.4 g cm-3 during year 1981 to 2010 (fig. 3).

Fig3: Status of bulk density of topsoil and subsoil in year 1981 and 2010

1.3 1.3

1.4

1.3

1.0

1.1

1.1

1.2

1.2

1.3

1.3

1.4

1.4

1.5

1.5

0-20 20-40

Depth (cm)

Bulk

dens

ity (g

.Cm

^-3)

1981 2010

0.6

0.3

1.1

0.7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-20 20-40Depth(cm)

Org

anic

Car

bon(

%)

1981 2010

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Blocking of the soil pores occurs mostly in the upper soil layer because irrigation with wastewater isdegradation of aggregate stability, resulting the soil compaction, and a decrease in soil aeration. (Magesan,2001). Mathan (1994). Reported that B.D increased in topsoil because suspended solids present inwastewater may accumulate and physically block water conducting pores, thereby leading to increase of theB.D of topsoil.

Conclusion

T tests were performed to investigate the changes of soil properties under municipal wastewaterirrigation. The results indicated that use of untreated municipal wastewater significantly decreased saturatedhydraulic conductivity and soil reaction of topsoil (p<0.05). Irrigation with wastewater also increased soilElectrical conductivityof subsoil and bulk density of topsoil significantly (p<0.05).

References

Abu-Awwad AM, 1996. Irrigation water management for onion trickle irrigated with saline drainage water,Dirasat, 23 (1) (1996) 46–55.

Ben-Hur M, 2008. Seal formation effects on soil infiltration and runoff in arid and semiarid regions underrainfall and sprinkler irrigation conditions. In: Zereini,

Bhardwaj AK, Mandal UK, Bar-Tal A, Gilboa A, Levy GJ, 2008. Replacing saline sodic irrigation water withtreated wastewater: effects on saturated hydraulic conductivity, slaking and swelling. Irrig. Sci. 26,139–146.

Chen Y, Wang CX, Wang ZJ, 2004. Assessment of the contamination and genotoxicity of soil irrigated withwastewater [J]. Plant and Soil, 261: 189-196.

Cook FJ, Kelliher FM, McMahon SD, 1994. Changes in infiltration and drainage during wastewater irrigationof a highly permeable soil. J. Environ. Qual. 23, 476–482

Coppola A, SantiniA,BottiP,Vacca S, Comegna V, Severino G, 2004. Methodological approach forevaluating the response of soil hydrological behavior to irrigation with treated municipal wastewater.Journal of Hydrology 292, 114-134.

Dawes L, Goonetilleke A, 2006. Using multivariate analysis to predict the behavior of soils under effluentirrigation.Water Air Soil Poll. 172, 109–127.

Domlngues ME, Carriloo A .OrtegaA,2004. Wastewater reuse in valsequillo agriculture area, Mexico:environmental impact on groundwater[J]. Water Air and Soil Pollution, 155: 251-267.

Gharaibeh MA, Eltaif NI, Al-Abdullah B, 2007. Impact of field application of treated wastewater on hydraulicproperties of vertisols.Water Air Soil Poll. 184, 347–353.

GoldbergS,SuarezDL , and Glaubig RA, 1988. Factors affecting clay dispersion and aggregate stability ofarid-zone soils . Soil Sci. 146:317-325.

Gupta AP, Narwal RP, Antil RS, 1998.Sewer water composition and its effect on soil properties. BioresourceTechnol. 65, 171.

Gupta RP,Dakshinamurthi C,1989. Procedures for physical Analysis of Soil and Collection of Agrometeoro-Logical Data. ICAR, New Delhi, India.

Heidarpour M, Mostafazadeh-Fard B, AbediKoupai J, Malekian R, 2007. The effects of treated wastewateron soil chemical properties using subsurface and surface irrigation methods. Agric. Water Manag. 90,87–94.

Jueschke E, Marschner B, Tarchitzky J, Chen, Y, 2008. Effects of treated wastewater irrigation on thedissolved and soil organic carbon in Israeli soils. Water Sci. Technol. 57, 727–733.

Khai NM, Tuan PT, Vinh CN, Oborn T, 2008. Effects of using wastewater as nutrient sources on soilchemical properties in peri-urban agricultural systems. VNU Journal of Science, Earth Sciences, 24:87-95.

Lado M and Ben-Hur M, 2009. Treated domestic sewage irrigation effects on soil hydraulic properties in aridand semiarid zones: A review. Soil & Tillage Research.

Lado M, Paz A, Ben-Hur M, 2004. Organic matter and aggregate size interaction in saturated hydraulicconductivity. Soil Sci. Soc. Am. J. 68, 234–242.

Lado M, Paz A, Ben-Hur M, 2004. Organic matter and aggregate size interactions in infiltration, sealformation and soil loss. Soil Sci. Soc. Am. J. 68, 935–942.

Magesan GN, 2001. Changes in soil physical properties after irrigation of two forested soils with municipalwastewater.New Zealand forest Research Institute. Nomber2767.

Magesan GN, Mclay CDA, Lal VV, 1998. Nitrate leaching from a freely-draining volcanic soil irrigated withmunicipal sewage effluent in New Zealand. Agriculture,Ecosystems& Environment 70:181-187.

Intl. J. Agron. Plant. Prod. Vol., 4 (5), 1023-1028, 2013

1028

Mandal UK, Bhardwaj AK, Warrington, DN, Goldstein D, Bar-Tal A, Levy GJ, 2008. Changes in soil hydraulicconductivity, runoff, and soil loss due to irrigation with different types of saline-sodic water. Geoderma144, 509–516.

Mathan KK, 1994. Studies of the influence of long-term municipal sewage-effluent irrigation on soil physicalproperties.Bioresource Technology 48:275-276.

Mohammad MJ, Mazahreh N, 2003. Changes in soil fertility parameters in response to irrigation of foragecrops with secondary treated wastewater, Comm. Soil Sci. Plant Anal., 34 (9 & 10):1281–1294.

Mohammad Rusan MJ, Hinnawi S, Rousan L, 2007. Long term effect of wastewater irrigation of forage cropson soil and plant quality parameters. Desalination 215 :143–152.

Oades JM, 1984. Soil organic matter and structural instability mechanism and implications for management ,P:319-338 .

Piccolo A, pietramellara G , mbagwu JSC, 1996. Effects of coal derived humic substances on water retentionand structure stability of mediterranean soils , soil use manage, 12,209-213.

Rattan RK, Datta SP, Chhonkar PK, Suribabu K, Singh AK, 2005. Long-term impact of irrigation with wastewater effluents on heavy metal content in soils, crops and groundwater-a case study. Agr.Ecosyst.Environ. 109, 310.

Siebe C, 1998. Nutrient inputs to soils and their uptake by alfalfa through long-term irrigation with untreatedsewage effluent in Mexico. Soil Use Manage 13: 1-5.

Siebe C, Cifuentes E, 1995. Environmental impact of wastewater irrigation in central Mexico: an overview. IntJ Environ Health Res 5: 161-173.

Siegrist RL, 1987. Soil clogying during subsurface waster infiltration as affected by effluent composition andloading , J. Environ . Qual . 16:181-187 .

Tabari M and Salehi A, 2009. The Use of Municipal Waste Water in Afforestation: Effects on Soil Propertiesand Eldar Pine Trees.Polish J. of Environ. Stud. Vol. 18, No. 6, 1113-1121.

TarchitzkyJ,Golobati Y, 1999. Reclaim wastewater effects on flocculation value of montmoriolite andhydraulic properties of a sandy soil .Soil.So .Sic .Aus .J . 63: 554-560 .

Vaseghi S, Afyuni M, Shariatmadari H, Mobli M, 2005. Effect of sewage sludge on some nutrientsconcentration and soil chemical properties. Journal of Isfahan Water and Wastewater, 53: 15-19 (inPersian).

Vinters AJA, 1983. The effect of suspended solids in wastewater on soil hydroulic conductivity. verticaldistribution of suspended soilds . Soil.Sci .Soc. Aus . J. 47:408-412.

Wang JF, Wang GX, WanyanH,2007. Treated wastewater irrigation e_ect on soil, crop and environment:Wastewater recycling in the loess area of China. Journal of Environmental Sciences 19:1093–1099.

Yang HX, 2002. Effects of irrigation with wastewater on the crops in Datong, Shanxi China[J]. Agro-Environment and Development, 4: 18-19.